Friday, 2 December 2016

My digital back Nikon FE can achieve nice results with infrared photography. I have been incorrect in suggesting that the IR Filter needs to be swapped with a clear glass filter to achieve focus when using the bare sensor for infrared photography. This is a myth as I have found that infrared light works on a slightly different focal length, so no wonder I was having focus issues. On many old SLR lenses there is a red dot on prime and a curving red line on zoom, or a straight red line on zoom lenses like the Tamron SP 35-80 2:8. These red marks are there to re-adjust the focus for infrared film after having first focused on the subject via the split prisms in the view finder. An example is to focus on a subject at 2.5 metres but your red dot or line will be at say 3 metres, therefore you need to turn the focus so the 3 metre mark is on the main focusing mark and your infrared photo will then be perfectly focused when exposed. Update 17th Jan 2017 - I have since sanded a bit more off the rebated edge of the sensor so sinking it further into the film plane. This has improved my focus in normal colour (filter inserted) at F1.8 to a very acceptable level. Subsequently with the IR/AA filter removed and shooting on the bare sensor, my focus is much more in line with the normal focus marks on the lens and in the split prism viewfinder. There is still a small amount of difference as IR light travels at a different wavelength. Whether the bare sensor reacts the same as IR film is another matter. If you start adding say red or yellow filters to the front of the lens then this will also change the wavelength to focus. So I think it comes down to rebating the sensor to the best possible tolerance with the IR/AA filter installed and then conduct tests without the IR/AA to see where the focus is at with different lenses shooting in IR. Here is a good article on focussing in infrared. Focussing in Infrared

Nikkor and two Tamron zooms with red IR focus line.

Another lesson I've had to learn is the dreaded White Balance setting on the Nex. If you use the Auto White Balance setting your photos will have a red tinge and only very blue sky will be blue. But when you use the iOS Photos program and edit filters to Mono, Tonal or Noir, your black and whites will be superb. However you can get a more realistic initial infrared photo in colour if you learn how to custom set the WB to a test photo. These test photos can be of a grey wall or green grass. I suggest you check the Nex manual and the internet to learn how to do this. Once the WB is custom set for the light conditions, you will find that the other colour filters in iOS Photos (or I guess PhotoShop) will provide some exciting filters to your photos and the B&W photos will still be superb with no change from your auto WB setting.

To set the White Balance test photo through the Nikon you need to coordinate the shutters simultaneously at the correct speed. Well that is way too hard. So instead set WB manually on “‘K’ C.Temp/Filter” and try 2900K G9 or G8 as the green strength. This seems to give a pretty good result on a sunny day. Experiment with different K & G settings.

Auto White Balance result

White Balance setting 2900K G9

My previous post mentioned the light meter calibration for infrared. There is about 2 stops extra light striking the bare CMOS sensor than when it has the IR Filter attached (or located within the SLR body). As the SLR light meter is reading light from the mirror before it reaches the sensor, then the SLR is no longer matching the Nex bare sensor reading. My really easy fix is to set the Nikon at 1600 ASA and the Sony Nex at 400 ISO. This brings the light meter to a near correct calibration. I have found in sunny light I get a more exact calibration with the Nikon adjusted to the next mark which must be 2133 ASA. But a few test shots and some tweaking of the ASA approximately 2 stops above the ISO will give you the correct calibration for the light your working with. You can use the compensation dial to tweak the exposure instead of moving the ASA.

Infrared photography was not my initial reason for inventing this Nikon/Nex hybrid camera. But it has shone through as a fantastic concept for this camera project. Infrared photography opens up a whole new dimension and to be able to combine this with SLR cameras and lenses that were designed to use infrared film is just awesome. If you are thinking about converting a DSLR to infrared then I would strongly suggest you look at this option of using a Sony Nex as the electric film on your favourite SLR kit that has been sitting in the cupboard feeling very unloved for the past 15 years.

If you are just going to use this camera for infrared then you do not need to worry as to whether or not you can fit the IR Filter up behind the mirror of the SLR. For specifically as a dedicated infrared SLR, you can convert any SLR. Now there is a strong statement but I believe this to be correct. You only need to remove the IR Filter from the Nex APS-C sensor and rebate the sensor to the exact Film Plane measurement. It's your call whether to modify the existing camera back permanently, or make a custom back so you could still change back to film. You should make a custom back for collector cameras and keep the original in tact as good quality film cameras are increasing in value now.If you have any queries or need advice if tackling this project then I am happy to assist.Robin. xovercameras@gmail.com
Click on the photos to enlarge.

Wednesday, 23 November 2016

Swap the IR Filter with Clear Glass

Well this has been a fun adventure. The IR/Lens filter I have fitted to a frame, which mounts up behind the Nikon mirror, is quickly replaced with a clear glass filter enabling the Nikon to photograph onto the bare sensor of the Nex. The clear glass is from a microscope slide and it protects the sensor from some dust that could come from the lens side of the shutter. Dust is my enemy now as I suspect that a sensor with the filter removed is more susceptible to dust than normal as the electric field is on the face of the sensor. Where as at manufacture the IR filter is fitted on a small frame 1.5mm from the sensor face and seals off the space between, which maybe reduces the static dust attraction at the outer glass face (another theory).

What has been interesting is the extra amount of light that now hits the sensor which makes the Nikon light meter out by about 2 stops. The photo exposures seem more sensitive to aperture adjustment. I was using a Leitz Elmarit 28 lens which has 1/2 stop adjustments and the variance shows significantly as compared to normal photos with the IR filter in place. Thinking about the light meter issue I concluded that the Sony engineers have to make the IR/Lens filters to a particular density so that the sensor calibrates exactly to the Calibration Standards for light meters (basically the sensor is the same as film). Which is why when I fit the 2012 CMOS sensor (with filter) to a 1980 Nikon, the sensor absorbs the correct illumination to match the Nikon light meter readings. When I remove the IR filter, the Nikon light meter is giving a reading as bounced off the mirror, which is now not matching the extra illumination the bare sensor receives during an exposure. Reading Wikipedia this same situation occurs when infra red film is used and the film camera's light meter has to be recalibrated to suit that specific IR film.

As I'm using a rather unique camera, I came up with a simple solution to fix the light meter calibration. I set the Nikon to 1600 ASA and the Nex to 400 ISO effectively 2 stops difference. This worked a treat and gave good images with the speed and aperture needles in alignment. I could then make fine tuning adjustments as normal with the Nikon's exposure compensation dial. The other benefit was I need to keep the speed over 125 as I shake and a 1600 ASA on the Nikon is a real help for this.

The photographs that can be produced with the IR Filter removed can make for some interesting black & white results. I don't have photoshop, just Preview and Photos on an iMac. Photos Edit has some B&W Filters that change the infra red photo to Mono or Tonal or Noir which give some great variations to a B&W image. Ming Thein did a lot of work with a Sony Nex with filter removed and there are some great shots on his album Multispectral . There is no reason that images to this level of excellence could not be produced with a SLR/Nex modification that I am working with here - provided that is you are a better photographer than me.

Below is a collection of some shots I quickly took to give you some idea of what a bad photographer with the shakes can produce from this camera. Click image to expand. Recently excerpts of this blog appeared in the Flipboard app resulting in a quick jump to over 5,000 views and 1,000 YouTube. It is pleasing to see so many take an interest. But when is someone else going to build one of these fantastic cameras? All the info you need is on the links in the top right of this page. Enjoy. RG.

Tuesday, 8 November 2016

Learning to use the Nikon FE with electric film

Nikon FE & Tamron SP

I have had the Nikon FE working with the Nex electric film for a few weeks now and ironed out some bugs. I have even discovered a few different ways to use it and a few surprises that I did not think possible.

My old MD11 motor drive has packed it in, but I have left it on as I prefer the handle grip and the extension of the battery compartment means I can fix a tripod or the Metz flash to the tripod mount. The camera is just more stable with the MD11 attached.

Playing around with the Nex settings I found I could custom set the centre wheel button to the ISO setting. This has made it really quick to change the ISO which needs to match the ASA on the Nikon. I shake a bit so this is handy for me to keep the Nikon speed above 125th in most conditions. The camera worked very well on 3200 ISO&ASA at an indoor conference with no flash.

Nikon FE digital with Metz flash

Speaking of using a flash, I tried the Nikon out with my old Metz 45CT flash attached. You would not want to connect this powerful flash to a DSLR as it could melt the electronics. But running off the SLR Nikon is what it is made for. The results have been terrific and setting the Nex to post process out the noise works well. Click this Lorikeet photo to see the result.

I've fixed a small raised rubber stopper to the Nex shutter button which makes it easy to trigger with my thumb knuckle without looking for it, as the Nex is inverted. I use the Nex in a couple of speed settings to electrify the sensor. If I want a bit of time to adjust focus, I set it to 6 seconds. Then I trigger the Nex, fine tune focus and fire off the Nikon before that time. The Nex then processes the shot, which can be a bit slow if the Long Exposure NR is on. The other method is to set the Nex to Bulb. I then trigger the Nex and fire off the Nikon whilst the Nex is held on. Processing can be short or long depending on the time the sensor was electrified. I keep auto Playback turned off as this slows things up. Just press the Playback button whenever I need to check a photo.

Something unexpected has turned up. Naturally the Nex is set on Manual but if I have it set on Bulb and put the Nikon on Bulb and hold the Nikon shutter open, then the Nex adjusts automatically to the light coming in and gives perfect Live View pretty much without having to adjust the lens aperture setting. But if I have the Nex set at say 6 seconds, the Live View just whites out until I start adjusting the speed on the Nex and aperture on the Nikon until the settings are close to what the Nex light meter is recording. So using the first method with both on Bulb I can frame a shot perfectly and play around with focussing using the Nex LCD and its Manual Focus assist button to zoom in. Also it's Focus Peaking Level works if you need that sort of thing.

The Nikon FE is renowned as an extremely good night time camera. It's versatile light meter will hold the shutter open for over an hour to expose an image. With good quality colour film you can get some outstanding results.

Nikon FE 200ASA film
3 minute exposure

So I thought I would try the electric film setup at night. Using a 50mm Nikkor set at 1:8, Nikon on auto speed and Nex on bulb, I put a rubber band around the Nex to hold the sensor on and tripped the Nikon shutter. It wasn't real dark so the Nikon exposed in about 60 seconds. I released the Nex and played back the shot. It was covered in multi coloured spots which I googled and found they were hot spots on the sensor commonly called noise. So I repeated the process a few times with the Long Exposure NR on. Well the Nex takes about the same time as the exposure to then process out the noise, quite a wait between shots. This did work and the photos were a lot better. But there is a chalk and cheese difference between digital and film when it comes to night time photography. I will experiment some more and might do some simultaneous photography using 2 Nikon FE's one with film and one with electric film. Should be an interesting comparison. Although I am a bit dubious whether the Nex can handle an exposure longer than a few minutes.

Another surprise was the ability to shoot movies. This just involves holding the Nikon shutter open in Bulb, adjusting the lens aperture to an average setting and focusing. Click movie and the Nex adjusts the light intake and shoots a pretty good movie with sound. So I guess this means the Nex does not need its shutter for framing in movie mode.

The Nex certainly cannot take a photo by itself though. What I mean by that is the Nikon shutter is held open whilst the Nex is triggered at a speed it's light meter is asking for. The photo is always overexposed and pretty corrupted. Obviously the sensor needs a shutter to close off the light for a brief moment to process the shot. Anyway that's not important as the photos are excellent with the Nikon taking the shots which is the purpose of this project.

I have set up a web site that explains how to fit a Nex to an SLR and a few other tricks to make it all work. Even a page on how to make a custom rear door. Camera conversions

Summarising this project I can qualify that it has been an outstanding success and I couldn't be happier with the way the camera works and the quality of the photos. When I started the project I was pretty sure it would take good photos but I never expected Live View or Movie to work so well. The action of triggering the Nex before the Nikon is something I am getting used to. It is a bit heavy with the MD11 attached but it feels great to hold this way and quite well balanced. If your contemplating this project then I highly recommend it as the end result is very satisfying.

Monday, 10 October 2016

How to make a Film Camera into a Digital Camera

In early September I started this project with very little idea as to how this could be achieved, or whether it was even possible. I was inspired by Oliver Baker's work on his "franken camera" project with a range finder Konica and a Nex 5. From that I had a few ideas I wanted to try. The biggest hurdle to overcome was installing the sensor at the film plane without it hitting the shutters. If this was not possible then the project was dead. The idea to install the sensor filters on the inside of the Nikon shutter was my breakthrough moment which enabled the sensor to be rebated into the film plane to a point where it achieves perfect infinity focus and yet is still clear of the shutters. The bonus of this method is the infra red filters can be removed for shooting with a bare sensor. Many DSLR owners are getting this conversion done for multi spectrum and astronomy photography. This 1980 Nikon FE can swap to either spectrum in a minute.

I took a few wrong turns with this project. My first idea was to use extension PCB ribbon cables for which I paid for drawings ready for production. However at $800 AUD that idea died. I then tried to meld and scallop a Sony Nex 5 onto the Nikon back. This looked good but the battery had to be installed in the motor drive and a shutter switch fitted elsewhere. Subsequently during one of many trial installs the motherboard went up in smoke. This turned out to be a bonus as the replacement Sony Nex 3 was a lot easier to install complete including battery. Meaning I could still use the motor drive.

Below are photos of the working 1980 Nikon FE with "electric film" provided by a Sony Nex 3 with a 14mp APS-C CMOS Sensor at 1.5 crop. In my next post I will go into detail just how the camera works, a few sample pictures and a nice surprise was it takes really good movies too as I did not expect it to be able to do this.

Filters removed from sensor. Installed in a metal frame which inserts behind
mirror up against the inside of the Nikon shutter frame. The blue tape
is just to pack out the sides a bit as the dimensions are critical to
prevent mirror lock up.

The sensor is allowed to float via the tape so it drops into the film plane.
Note how deep the rebate has to be to obtain the correct film plane position.

Looking into the Nikon with mirror up and prior to installation of the filters.

Filters are installed on the other side of the camera shutter frame.
The film rails have been widened by 0.5mm each side to allow the
rebated APS-C sensor to drop in between them. This issue resolved.
Read my Detail Page on fitting a sensor to the film plane

Sunday, 18 September 2016

The Sony sensor has been checked over and blueprinted to within 0.02 at all 4 corners. Undeveloped film is 0.13 thick so the tolerances are fairly tight. I see what Nikon mean when they say the Film Plane only has give or take 0.02mm max. These tiny differences make a big impact on lens focus. On the results I have it is looking pretty close. It is just difficult to get the micrometer into the rebate edge as the circuits are above it. Given the results today I wouldn't mind just taking another Bee's D off to see a slight improvement at F1.8. The other aperture settings look pretty good. But then I am no photographer so it will be interesting to see what you expert photographers think of the results. Feel free to criticise and cann them.

I have photographed some old cameras at distances of 600mm, 1500mm and 3500mm at various F stops. The speed was left up to the Nikon on Auto and ASA 200. The Sony Nex was set at ISO 200, 5 seconds time and default F1.0 with no lens. The Nikon split screen focus was on the middle of the self timer lever on the Leica. These photos are just to show that a sensor can be installed in a film SLR camera and get reasonable focus results. It won't compete with say a Canon 5D but there are some fun benefits to having the old SLR working again.

F1.8 1000th 600mm

F4 250th 600mm

F11 300th 1500mm

F8 400th infinity focus

F11 70th infinity focus

That's all the blue printing of the sensor adjustment for now. I am pleased with the results and I hope you are too. Seeing as I have had success with fitting the sensor at the film plane position it is time to move on to fitting the remnants of the Sony to the Nikon back.

I have shelved the idea of keeping the Sony complete even though I spent a lot on the design of the extension cables. Instead I am going to fully dismantle it and see where on the Nikon back I can fit everything. Then design some sort of retro cover for it. This may have some benefits as I should be able to get the motherboard to see the circuit board (there are two little eyes that line up with the sensor that I figure make Live View work and the other may be it's auto focus). Live View might work when the Nikon is clicked at Bulb to open it's shutter so the Sony sensor can get a look at the view through the lens.

The main theme is to keep the Nikon as a film camera, so all that stuff in the Sony has to fit only on the film back so I can just swap it for a film back when required. I also want to use the digital back on my Nikon FE2.

Thanks for taking an interest. Feel free to comment below. I would appreciate your thoughts on the Focus. It still seems a little blurry in the distance at infinity so another tweak with the sandpaper might fix this.

Old 35mm Film Cameras can go Digital

Saturday 17th September 2016
I have spent half the day sanding down - remounting - testing, sanding down - remounting - testing, sanding down - remounting - testing. To eventually obtain focus on the cupboard knob at Nikon settings of Auto speed + F1:8 using a 1980 Nikon FE + Series E 50mm lens with a digital Sony Exmor 14mp APS-C cmos sensor now successfully mounted at the Film Plane.

Focus on door knob at F1.8 at approx 3.5 metres.
Sensor is almost at correct film plane.

My previous posts suggested that if the sensor was to come into contact with the film shutters, then they could be removed from the sensor and a replacement infra red filter could be mounted on the end of the lens. This was incorrect. The IR filter is attached to a thin lens plate. These two have an affect on focus. If removed the sensor has to be moved forward the equivalent distance to obtain focus. So it is a futile exercise thinking this will create space to adjust the sensor before it touches the camera shutters.

To overcome this I mounted the IR & Lens combo at the rear of an SP Tamron with an adaptall Nikon mount. This did work on retaining the same focus but the colour was washed out (probably as I had it round the wrong way).

I then studied the camera internally and could see that there was room behind the mirror to mount the IR & Lens combo against the shutter frame. Using a simple L shape frame of builders flashing with the filters mounted in the middle, this slips nicely in behind the mirror and does not foul any operation of the camera. Now I had a bare CMOS sensor with plenty of adjustment room to the shutters with the IR filters mounted just on the inside of the shutters that provide the necessary focus and infra red filtering.

The sensor has a frame around it to keep the IR filter & lens above the sensor. Under this frame is a glass screen covering the sensor but this screen is 24.6mm wide. The width of the film rails is 24mm. The sensor could not be moved any closer unless this matter was resolved. I decided to not risk breaking the glass and felt that removing 0.4mm off the side of each film rail would make no difference to the camera being able to shoot film. It would just leave uneven edges if developed as prints - but who does that these days. All my developing involves scanning which crops the film as a neat rectangle anyway. So I filed each rail a bit thinner.

Now I had both plenty of depth to the shutter and width between rails to enable the sensor to move down into the film box rectangle. The sensor mount frame is a very hard plastic and I found the best way to reduce it was with plasterboard finishing sandpaper. After each sanding session I measured the small edges with a micrometer. Once all edges were near equal the sensor was reinstalled and tested. Where the focus disparage really shows up is at F1.8. I placed a chair with magazine copy 1 meter in front of my intended target and this helped identify that the focus was gradually coming closer after each adjustment session with the sandpaper.

Sensor adjusted for depth with filters removed.
Still good clearance from the shutters.

All SLR Cameras Possible
Even at the adjusted depth to the film plane, the hinges of the Nikon shutter do not touch the sensor. So now I can move the sensor into the centre. If they did touch the shutter then the sensor IR filter frame could be easily sanded down. This is a real winner for any film camera now. My Canon A1's have a depth to shutter of 2mm so now the adjusted sensor will fit it also. If it fits both the Canon and Nikon then I will assume that this method will work for many film SLR cameras. The issue is no longer the sensor touching the shutter, but rather can the IR Filter/Lens combo be discreetly mounted behind the mirror against the inner frame of the shutters.

Lens Theory
As the Exmor CMOS sensor has the small frame to support the IR Filter/Lens a set distance away from the sensor, I theorise that by moving them to the other side of the shutter, so increasing the seperation distance, actually decreased the amount I had to remove from the sensor support to achieve the exact film plane mounting position.

Infra Red Photography
I experimented with removing the IR/Lens and just shooting with the bare sensor. These photos can be easily converted by Photoshop into stunning black and white. See this link. Mingthein Blog But the focus is not correct without the IR/Lens and the sensor would need to be moved further in to compensate. However when shooting with no IR/Lens at smaller apertures the depth of field compensates the focus and the shots are reasonable. So it would be possible to take more off the sensor mounts to make it accurate focus for Infra Red photography and then add set height packers when shooting with the filters on for normal photography. The internal filter frame behind the mirror holds easily in situ with one piece of black tape and can be installed or removed in seconds. A set frame packer could be easy to make for the sensor adjustment. So the camera could be swapped from normal to IR photography in a minute or so. That's one up for film cameras compared to DSLR's.

Infra Red (in mono) when filter is removed.
Focus is not correct when IR/Lens are removed.

Focus accuracy is improved dramatically.
A bit more sanding and it will be accurate.

My next post will show a number of photos with the sensor correctly on the film plane. I will make them available for download in JPEG and RAW should you wish to check them in your software. By all means check the Exif files. They will read - Sony Nex - ISO 200 - F1.0 - Lens n/a - Speed 5 seconds. The Nikon FE took these photos not the the Sony.

As I have received a few enquiries as to how I am achieving this, once the camera is complete and mounted on the Nikon I will produce an informative manual in PDF explaining all the steps I took. This will save countless hours of work should you now be encouraged to take on this great project.